When are Tales generally announced?

I don't exactly "follow" this, but the announcement of an additional Episode (13) for Tales of Zestiria the X (that will air around 1 month after episode 12) got me thinking that maybe they'll announce something at the end of it.

I do find it odd as well that we have to wait over a month to finally see the finale of this series, part of me is thinking partial announcement, other part of me just thinking maybe animation company scheduling/figuring out maybe how to end off the series.